If 31.8 grams of licl are dissolved in 225 grams of water, what is the concentration of the solution in percent by mass?

How did planetesmals form planets? a. they broke apart into smaller chunks.b. they collided and stuck together.c. they cooled and pulled ice together.d. they began to rotate.

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

Define the kinetic molecular theory